Mate panel lockups

Can't explain how I get it to happen, but quite often I have a locked up panel, symbols gone, no more reaction of the panel. Shutdown is only possible from the console. If no console is around, I need to use the reset button.

What can I do to improve this? Go away from Lightdm? I am used to this combination since Wheezy offered Mate from Backports.

Re: Mate panel lockups

Can't explain how I get it to happen, but quite often I have a locked up panel, symbols gone, no more reaction of the panel. Shutdown is only possible from the console. If no console is around, I need to use the reset button.

What can I do to improve this? Go away from Lightdm? I am used to this combination since Wheezy offered Mate from Backports.

Thanks, rolfie

I use Slim and have never experienced this. I installed MATE at the original system install, if that makes a difference. I would try Slim and see how that goes.

Re: Mate panel lockups

@rolfie, I run ascii/mate with slim. I originally preferred lightdm but had some (unremembered) issue and made an unwanted switch to slim. Slim has grown on me and I find it dependable even during experimentation it has been a solid performer.The point is, I detested slim and now I prefer it. Just my experience.

Re: Mate panel lockups

rolfie, I'm also on Devuan ASCII with Mate 1.16 and Lightdm, manually installed. My system started out as MiyoLinux.

Are you using a background image for your panel? Check by right-clicking on panel -> Properties -> Background. When I was using a background image, my panel was unstable and sometimes icons would disappear and/or panel would lock up on me. Choosing "None (use system theme)" for panel background made all my panel issues go away.

Re: Mate panel lockups

GNUser wrote:

Are you using a background image for your panel? Check by right-clicking on panel -> Properties -> Background. When I was using a background image, my panel was unstable and sometimes icons would disappear and/or panel would lock up on me. Choosing "None (use system theme)" for panel background made all my panel issues go away.

Re: Mate panel lockups

Another thought: Many MATE components use dbus for interprocess communication, so mate-panel almost certainly uses it as well. dbus logs to /var/log/syslog. Does anything interesting show up in the syslog when the panel becomes unresponsive?

Re: Mate panel lockups

I have experienced the same problem, compounded by issues of the panel icons re-ordering.

I asked the question on the Debian forum but received no response. For convenience of members here, I've quoted the posts below:

NFT5 wrote:

For my everyday work I use Jessie and it is wonderfully stable. I don't usually upgrade immediately after a new version release, waiting for the bugs to be ironed out or solutions/workarounds found. So, over the last couple of months I've had a few tries at getting Stretch installed and running. Not really successfully so far. Also tried MX17 and Devuan Ascii with the same results - random crashes which I'm reasonably sure have something to do with the MATE panel.

Google searches don't yield much except a few mentions of similar problems - mouse becomes unresponsive, then keyboard and the only way out is a hard reset. There seems to be some thinking that it is GTK2/3 theme related and so, yesterday I tried a vanilla installation using the TraditionalOk theme (reported as being stable), without any other changes. Went fine for a few hours then, without warning, crashed again. Same symptoms as previously with mouse becoming less and less responsive, then keyboard not responding and all the while the HDD light being constantly on. I just walked away in disgust and did a hard reset this morning.

Upon restarting all my application launcher icons in the top panel had crowded across the the left hand side and reversed order. Same as what has happened previously and there have been some mentions of this in Google search results.

Problem is that I haven't really found a solution since I, and apparently others, don't really know the cause. There seems to be nothing specific that triggers this - on previous tries it has run for days without a problem and then crashed again 30 minutes or less after recovery. Seems to be completely random.

I'm running MATE 1.16 now but have tried 1.18 before, without any improvement. I've seen a mention that 1.20 may have fixed it (fully GTK3) but can't find any confirmation.

Following is an extract from syslog, starting about 15 minutes before the last crash which happened at 21.02, and then the log continues for some time after that. There are another 7 hours of log, but nothing any different.

Seems a bit amusing that it carried on getting the weather updates but then later in that log I see memory problems. Kinda like rearranging the deck chairs on the Titanic. Not only that but their call of -5C was a bit off the -7C that we hit at 6:30 this morning. :roll:

More seriously, I'm hoping that the brains trust here may see something that I haven't or give me a hand to track this problem down.

NFT5 wrote:

Well it seems I may be making more progress with this than anyone else.

I have at least been able to create, at will, the symptom of panel icons re-ordering and displaying on the left end of the panel. Just add a new icon/launcher and restart the machine. New icon, previously positioned at the far right now appears at the far left.

The good thing is that there seems to be a solution for this. Open Mate-Tweak and click on "Save Panel Layout". Restart and icons are where they should be.

However, there is some weirdness with this. When saving the panel layout I get a notification that my settings have been saved in /usr/share/mate-panel/layouts/{username}-tweak.layout. However, the file is not there. Looking elsewhere, on the basis that the settings must have been saved somewhere, I eventually found the file in /tmp, along with another file named {username}-tweak.panel.

The problem now is that /tmp files are not permanent so my settings may be lost.

I've never experienced this problem in Jessie or Wheezy, but, of course, they were running earlier versions of MATE and I suspect that MATE may be the culprit here. So, it seems that MATE is not saving panel changes for placement and ordering automatically/immediately although it is saving the icons/launchers. I still suspect Debian may also be complicit here, given that I've had no problem with MATE 1.16 running in Jessie.

I can't understand why the problem seems to be relatively rare - surely something like this would be rife in Mint and Ubuntu, yet there are only a few mentions....and no real solutions........yet.

Continuing to work on it.

I understand that the above relates to Debian but I have the identical problem with Ascii and I suspect that they are sufficiently alike that a solution for one may work with the other.

Subsequent to the above my research has led me to thinking that the issues are GTK2/3 related. I have been able to stop recurrence of the panel crashes by selecting either of the Traditional themes and keeping customisation to an absolute minimum. Most other themes inevitably lead to the panel crashes. Selection of a stable theme seems to have to be made on a clean installation - once an installation has suffered a panel crash changing the theme doesn't work to stabilise it.

I've tried MATE 16, 18 and 20. Both 16 and 18 suffer from the problem while, so far at least, 20 seems stable.

What I haven't been able to do is find the actual cause and a proper fix, however the above is a partial workaround.

Re: Mate panel lockups

From the (CRON) error (can't fork), the oom-killer and Out of memory: messages it looks as if your system ran out of memory. How much ram and swap space does it have? What does free -mt say when it's running OK and when it's having problems?